PHASE-MATCHED 2ND HARMONIC BLUE-LIGHT GENERATION IN ION-IMPLANTED KNBO3 PLANAR WAVE-GUIDES WITH 29-PERCENT CONVERSION EFFICIENCY

We report for the first time to our knowledge, noncritical phase-matched second harmonic generation in an ion-implanted KNbO3 planar waveguide. The guided TM0 mode of the fundamental wave (868 nm) is converted into the second harmonic TE1 mode (434 nm). From 1.3 kW of internal fundamental peak power 385 W second harmonic blue light is generated giving a conversion efficiency of 29%. A comparison of the measured and the theoretical efficiencies implies that phase-matching is achieved over the full waveguide length. Based on these first experimental results we estimate that 100 mW of blue light can be generated from 400 mW of input power using an optimized KNbO3 Planar waveguide of 1 cm length.